Continued: Virginia Johnson, part of husband-wife team that transformed study of sex, dies at age 88

"There was a lot of grief," Johnson's son, Scott Johnson, recalled. "There were threats, things of that kind. She was a very strong woman."

As Masters' health was in decline in the 1990s, and Johnson was caring for him, he announced he was divorcing her, leaving her to pursue a sweetheart of his youth. The Masters and Johnson Institute closed in 1994 after Masters retired. He died in 2001.

Scott Johnson said his mother also retired in the 1990s.

But their work still fascinates and resonates. Showtime will debut a TV series in September, "Masters of Sex," based on Maier's book.

"She brought equality to women in the field of sexuality," Maier said. "Their studies underlined the power of female sexuality."

Along with her son, Johnson is survived by her daughter, Lisa Young, and two grandchildren. Private funeral arrangements were pending.